Conservation-tillage pollution claims hard to understand

As if the Environmental Working Group (EWG) isn’t challenge enough to farmers doing their best to provide adequate food and fiber to a rapidly increasing global population — while also doing their best to preserve the natural resources necessary to accomplish those goals — along comes another self-righteous organization to cast aspersions on a practice that allows some farmers to improve soil conservation.

The Union of Concerned Scientists (UCS) is taking no-till to task, claiming that the practice is linked to increased waterway pollution. A recent news release hit my e-mail box with that claim.

The ‘news’ item—and I use that term ‘news’ guardedly—suggests that “conservation tillage, turning or plowing the soil to kill weeds, may be linked to an increase in toxic algae blooms.”

The opinion piece — which is a more apt description — says the claim is based on “new research.” The toxic blooms come from runoff that carries phosphorus into waterways, according to the UCS.

Apparently, the UCS folk have no clear understanding of how conservation-tillage works. The process of “turning or plowing the soil to kill weeds,” does not fit the definition of most conservation-tillage practices and particularly not no-till, which minimizes soil disruption to seedbed preparation. Other practices, including reduced-till, ridge-till and other systems, vary in the amount of soil disruption used to plant seed. But plowing to kill weeds is not part of most reduced-tillage systems.

But no worries, the UCS offers options. “Sustainable practices, like cover crops, achieve all the suggested benefits of no-till and more, but the agriculture industry continues to push no-till,” according to a UCS spokesperson. They add: “Unlike sustainable practices, no-till depends on expensive purchased products. It’s good for the industry’s bottom line, not so good for the rest of us.”

I don’t disagree with the idea of using cover crops. Indeed, many practitioners of no-till, reduced-till and minimum-till rely on cover crops to provide the residue they need to hold moisture, increase organic matter in the soil and protect the land from water and wind erosion in the off-season.

Small grain stubble

Some also plant into small grain stubble and residue from a previous crop — which also helps prevent erosion through fall and winter months.

Some no-till farmers I’ve interviewed over the years also plant cover crops following fall harvest for the express purpose of holding soil over the winter and supplying residue at planting. Those cover crops also build organic matter and the root systems help move water deeper into the soil, stockpiling it for the next crop.

It’s not always feasible, however. Cover crops, like the plants that will follow them, require moisture. Apparently, UCS folk have never spent a winter in the Southern High Plains of Texas, where the wind blows strong and rainfall is uncertain.

Even with irrigation, the challenge of maintaining a cover crop throughout the winter may require more water than can be depended on or justified. Conserving water is also part of a sustainable system. Water demand for a cover crop must be balanced against the potential advantages. Sometimes it works out; sometimes not.

We’ve written many articles depicting the various ways farmers use reduced tillage practices, including cover crops, to improve soil conservation efforts, preserve water and prevent runoff. We’ve applauded efforts of those who found ways to improve stewardship — sustainability — while maintaining profitable yields. And still we have self-righteous organizations that hijack the term “sustainability” and define it in their own narrow terms. To be sustainable, a practice has to make sense. In some cases, cover crops fit that criterion. In some they do not.

Farming is not a one-size-fits-all proposition. Creativity and flexibility are part and parcel of any successful agriculture enterprise and trying to fit all operations into one pigeon hole is doomed to failure.